1. Field of the Invention
This invention relates to apparatus and a process for the removal of insoluble substances from a liquid, and more particularly, to the purification of a liquid by the gas flotation of insoluble dispersed materials from the liquid.
2. General Background
Many industrial processes such as mining and oil recovery operations involve the treatment or handling of a liquid which contains contaminates such as fine suspended solid particles or globules of oil or other liquid substances which are immiscible in the liquid. Often, these contaminants must be removed prior to subsequent use or disposal of the liquid. For example, contaminants picked up in water used in the beneficiation of minerals must be removed from the water prior to its reuse or disposal. Similarly, water used in oil operations such as secondary recovery usually contains dispersed oil droplets which must be removed from the water prior to its reuse in the oil recovery operations or prior to its return to the environment.
Many systems have been devised for the removal of the above-described contaminants from liquids. For example, insoluble contaminants are often removed from liquids in large settling basins. This treatment is generally ineffective for the removal of finely suspended solids or insoluble liquid droplets. Other purification methods are based on filtration, but the high cost of purchasing and maintaining filtration equipment militates against the use of these techniques in most industrial operations. One of the most commonly used methods for the purification of liquids containing solids or immiscible liquids is gas flotation. Gas flotation involves the use of very small gas bubbles to agglomerate or coalesce the contaminant particles and float them to the surface of the liquid where they are separated from the liquid. The present invention employs an improved gas flotation method for the removal of suspended contaminants from liquids.